Explain the difference between place theory and frequency theory in regard to perception of pitch.

Place theory is a theory of hearing which states that one's perception of sound depends on the place where each component frequency produces vibrations along the basilar membrane.
The frequency theory of hearing states that the frequency of the auditory nerve impulses correspond to the frequency of a tone, which allows one to detect its pitch.  The difference between the place theory and frequency theory in regards to perception is that, in place theory, the basic pitch determining mechanism is based on the location along the membrane where the hair cells are stimulated. The frequency theory on the other hand holds that whatever the pitch of a sound wave, nerve impulses of a corresponding frequency will be sent to the auditory nerve. 

The place theory of hearing is used to explain how we distinguish high-pitched sounds that possess a frequency that exceeds 5,000 hertz. ... In other words, different parts of the cochlea are activated by different frequencies. Each location on the basilar membrane possesses a particular characteristic frequency.